Age estimation, growth rate and size at sexual maturity of tigerfish<i>Hydrocynus vittatus</i>from the Okavango Delta, Botswana

Gerber, Ruan; Smit, Nico J.; Pieterse, G. M.; Durholtz, Deon

doi:10.2989/ajas.2009.34.3.5.981

Cited by 20 publications

(22 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The noticeable macroscopic characteristics during the various maturity stages of the testes have been recorded in Table . This table was developed specifically for the maturity identification of the testes from C. gariepinus (adapted from the features described by Cambray, , Booth & Weyl, and Gerber et al, ).The most prominent characteristic during the developing spermatogenic stages was the white ‘wavy fringe’ on the lateral region of the testes (Pieterse, Marchand, Dyk, & Barnhoorn, ; Wagenaar, Botha, & Barnhoorn, ). This area develops and becomes more prominent as more developing germ cells mature into spermatozoa during the late spermatogenic stage (Nibamureke, Barnhoorn, & Wagenaar, ).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

The urogenital papillae as an indicator of sexual maturity in male African catfish, Clarias gariepinus, (Burchell, 1822)

et al. 2019

View full text Add to dashboard Cite

The present study investigated a non‐invasive method based on macroscopic morphological features of male Clarias gariepinus for the assessment of sexual maturity stage. As African catfish cannot be stripped for semen as in most other fish species; they have to be killed to obtain semen from the testes. This method could be used to ensure that males used to obtain sperm are sexually mature to increase the concentration and quality of mature sperm for egg fertilization in the production of C. gariepinus. Morphological features including the length and width of the urogenital papillae (UGP), an external secondary sexual characteristic of C. gariepinus (n = 89) were measured and calculated as a percentage of total body length. The urogenital papillae length (LUGP) and width (WUGP) index of each fish were used and compared with the macroscopic and microscopic maturity stage of the testes. The results revealed that although positive, a significant correlation does not exist between the LUGP or WUGP and maturity stage of the testes. Therefore, although this procedure would be valuable as an initial non‐invasive assessment of maturity, it does not provide an accurate or reliable indication of the maturity stage of the fish.

show abstract

Section: Resultsmentioning

confidence: 99%

“…Using criteria previously described by Cambray(), Booth and Weyl () and GerberSmit and Pieterse (), as guideline, the macroscopic and microscopic maturity stages of the testes of each fish were determined. Criteria for this assessment specific for male C. gariepinus were recorded and tabulated (Table ).…”

Section: Methodsmentioning

confidence: 99%

The urogenital papillae as an indicator of sexual maturity in male African catfish, Clarias gariepinus, (Burchell, 1822)

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Although it is difficult to infer the size of individuals based on isolated teeth, mature teeth of Nsungwe Hydrocynus sample compare favorably in size with immature individuals of H. vittatus (287 § 13 mm fork length; Gagiano et al, 1996) but not mature individuals (males >451 mm and females >522 mm total length; Gerber et al, 2009). It is tempting to suggest the presence of a smaller species or population of exclusively immature individuals, but specimens hail from well-sorted coarse-grained sandstones and therefore may simply reflect depositional environment.…”

Section: Methodsmentioning

confidence: 99%

Alestid (Characiformes: Alestidae) fishes from the late Oligocene Nsungwe Formation, Rukwa Rift Basin, of Tanzania

Stevens

Claeson

Stevens

2016

Journal of Vertebrate Paleontology

View full text Add to dashboard Cite

Alestidae is a clade of African characiform fishes including 19 extant genera and approximately 105 species that are known from Afro-Arabia, with records reported from the Eocene-Oligocene Jebel Qatrani Formation of Egypt, the Eocene Mahenge crater lake of Tanzania, and early Oligocene to Miocene sites on the Arabian Plate. Here we report the first record of alestid fishes from the late Oligocene Nsungwe Formation in the Rukwa Rift Basin of southwestern Tanzania. The Nsungwe alestid sample is composed of 92 teeth spanning a range of sizes and morphologies. Teeth are examined with regard to cusp number and organization, tooth position and replacement, and in the context of alestid jaw organization using modern, comparative representatives. Results suggest that at least two alestid taxa are represented in Nsungwe Formation localities. Hydrocynus teeth exhibit a single, conical cusp. Several of these specimens preserve a mesiodistally expanded crown and concave surface on the lingual aspect of the tooth. A second, unnamed taxon, with three morphological variants, is distinguished from Hydrocynus based on a multicuspid morphology of fully erupted teeth. The presence of these taxa in the late Oligocene of Africa below the equator provides key insights into the biogeography of the clade. Citation for this article: Stevens, W. N., K. M. Claeson, and N. J. Stevens. 2016. Alestid (Characiformes: Alestidae) fishes from the late Oligocene Nsungwe Formation, Rukwa Rift Basin, of Tanzania. Journal of Vertebrate Paleontology.

show abstract

“…In addition, Skelton (2001) has shown that southern African female tigerfish are generally heavier than males. This is certainly true for the Okavango, where in a sample of 208 tigerfish (~1:1 male:female ratio), all fish larger than 2 kg were female (see Gerber et al [2009] for data on fish lengthweight relationship and size at sexual maturity). Our data demonstrate that blood lactate increased with angling duration, up to approximately 6 mMol l -1 at 3-4 minutes.…”

Section: Angling Duration Versus Fish Sizementioning

confidence: 99%

Blood lactate levels as a biomarker for angling-induced stress in tigerfishHydrocynus vittatusfrom the Okavango Delta, Botswana

Smit

Howatson

Greenfield

2009

African Journal of Aquatic Science

Self Cite

View full text Add to dashboard Cite

Although critical in catch-and-release angling, no data are available on angling-induced stress in African gamefish. Blood lactate levels were used as a biomarker for angling-induced metabolic stress in tigerfish caught by angling in the Okavango Delta, Botswana. Blood was drawn and analysed for blood lactate from 66 anaesthetised fish. The landing time, handling time, body mass and total length were recorded prior to reviving and keeping the fish in aerated water for recovery before release. A strong positive relationship (r 2 = 0.607) was found between landing time and body mass, as well as significant elevations in blood lactate concentrations following rod-and-line angling, regardless of angling time. These data suggest that longer angling time significantly increases physiological stress, which may have an impact on breading success and mortality in tigerfish.

show abstract

Age estimation, growth rate and size at sexual maturity of tigerfishHydrocynus vittatusfrom the Okavango Delta, Botswana

Cited by 20 publications

References 25 publications

The urogenital papillae as an indicator of sexual maturity in male African catfish, Clarias gariepinus, (Burchell, 1822)

The urogenital papillae as an indicator of sexual maturity in male African catfish, Clarias gariepinus, (Burchell, 1822)

Alestid (Characiformes: Alestidae) fishes from the late Oligocene Nsungwe Formation, Rukwa Rift Basin, of Tanzania

Blood lactate levels as a biomarker for angling-induced stress in tigerfishHydrocynus vittatusfrom the Okavango Delta, Botswana

Contact Info

Product

Resources

About